But these movies and others could be derailed if actors and studios can't negotiate a new contract by the end of the month, when the current Screen Actors Guild pact expires. Despite several weeks of negotiations, there's growing pessimism throughout Hollywood that the sides will resolve their significant differences any time soon.

If they don't reach an agreement, actors could opt to strike early next month or work without a contract. For their part, studios could enforce a lockout by blocking SAG members from working on movies and prime-time TV shows. Although the lockout option -- full or partial -- has been discussed by some studio executives, such a move is considered drastic.

A protracted period of uncertainty is casting a pall over future film production. Just the threat of a strike has put a crimp on local production, which was cited Friday as a factor in the state's highest unemployment rate for May in five years. Employment in the motion picture and sound recording sectors was down 4.4% from May 2007.

In anticipation of a possible actors strike, studios revamped their schedules last year so that most films would finish shooting by June 30. They've also virtually stopped greenlighting new movies, causing a sharp slowdown in production -- or a de facto strike -- that could drag on for months. Some executives speculate that the studios could push back start dates to early next year to hedge their bets.

"We're kind of in no-man's land right now," said Patrick Whitesell, a partner at the Endeavor talent agency. "When you're trying to plan your next move with your clients, you're handcuffed because so little is getting made."

Whitesell's clients include Christian Bale, who is headlining the fourth installment of the "Terminator" sci-fi franchise. In the event of a strike, it would be among more than half a dozen current productions forced to shut down. They include sequels to such hits as "Night at the Museum" and "Transformers," "The Da Vinci Code" follow-up "Angels & Demons" and a movie version of the Disney Channel series "Hannah Montana."

The studios have contingency plans for a strike that would enable filmmakers to continue some work on movies, completing special effects that don't require the use of actors, for example. But halting production for an extended period would be costly for the studios and jarring for the hundreds of actors, crew members and post-production technicians who would suddenly find themselves idled.

More than 1,800 people, both in the U.S. and abroad, are lined up to work on Disney's nearly $200-million-budget "Prince of Persia: The Sands of Time," a video-game-based tale starring Jake Gyllenhaal that's set to begin production in Morocco on July 28.

"Of course, we're concerned," said the film's producer, Jerry Bruckheimer. "We'd have to shut it down and everybody goes home. . . . But I can't believe either side wants a strike." Bruckheimer said if the production was delayed, the crew nonetheless would continue working on visual effects, editing, set building and other areas not requiring actors.

Moreover, if halting production pushes the eventual start date of "Prince of Persia" too far into the future, the film would risk missing its planned release date next summer.

Imagine Entertainment and Universal Pictures are counting on starting their nearly $150-million production of "Nottingham" in early August in Britain. A delay could ruin plans to shoot the fall leaves of the mythical Sherwood Forest on location. Not all feature film production would halt in the event of a strike, however.

SAG has granted waivers that would allow more than 350 independently produced films to continue shooting, such as the drama "Shrink," starring Kevin Spacey as a pot-smoking psychoanalyst, and "A Good Old Fashioned Orgy," a romantic comedy produced by Endgame Entertainment.

If it happens at all, a strike would probably not occur until after July 8, when a smaller actors union, the American Federation of Television and Radio Artists, will announce the results of a membership vote on its recently negotiated contract.

SAG is waging a long-shot campaign to defeat the accord, contending that it undermines the union's bargaining goals. SAG's efforts, however, were dealt a setback over the weekend, when about 250 actors, including Tom Hanks, signed a letter supporting the AFTRA agreement.